Disconnectors are small appliances inserted in drinking water distribution systems so as to prevent, in the case of a pressure drop upstream for any reason whatsoever, the water which is downstream and may be considered as polluted from being driven back upstream beyond the disconnector.
Such appliances have already been proposed for this purpose formed from a more or less cylindrical body with coaxial inlet and outlet, a central chamber having a discharge outlet towards the drain in case of feedback and membrane and valve sealing members upstream and downstream of this central chamber, allowing free passage of the water through the body of the appliance in normal operation and stopping the arrival of water coming from upstream as well as feedback of water coming from downstream in the case of a downstream pressure greater than the upstream pressure, the leaks of polluted water fed back which may occur penetrating into the central chamber and being discharged towards the drain.
Such appliances have not always the reliability desired because of hazards due to the membranes and to the seal of the valves which is not always perfect.